1. Field of the Invention
The present invention relates to a pixel structure and a fabricating method thereof, and more particularly, to a pixel structure and a fabricating method thereof in a transflective/reflective liquid crystal display (LCD).
2. Description of Related Art
Generally, LCDs can be classified into three types by different light sources, which are transmissive LCDs, reflective LCDs and transflective LCDs. With the development of portable electronics, emphasis is being placed on reflective and transflective LCDs that may utilize external light sources. However, in LCDs, when fabricating pixel structures of the conventional reflective or transflective pixel structure, fabricating a reflective layer is additionally required. Furthermore, extra fabrication processes are required to fabricate the reflective layer with an uneven surface to increase the effects of reflection of the reflective layer.
FIGS. 1A˜1I are schematic cross-sectional views illustrating the conventional fabrication processes of a pixel structure of a transflective LCD. Referring to FIG. 1A, first, a substrate 110 is provided. A gate 120 is formed on the substrate 110 though a first mask process. Next, referring to FIG. 1B, a gate insulation layer 130 is formed on the substrate 110 to cover the gate 120. Then, referring to FIG. 1C, a semiconductor layer 140 is formed on the gate insulation layer 130 on top of the gate 120 through a second mask process.
Referring to FIG. 1D, a source 152, a drain 154, and a patterned semiconductor layer 140′ are formed at the two sides of the semiconductor layer 140 through a third mask process. Furthermore, referring to FIG. 1E, a protection layer 160 is formed on the substrate 110 to cover the source 152, the drain 154, and the patterned semiconductor layer 140′. Next, referring to FIG. 1F, the protection layer 160 is patterned through a fourth mask process to form an opening 162 in the protection layer 160, and remove the protection layer 160 in a transparent region 164 at the same time.
Then, referring to FIG. 1G, the protection layer 160 is patterned through a fifth mask process to form a plurality of bumps 166. Referring to FIG. 1H, a reflective layer 170 is formed on the bumps 166 through a sixth mask process. Then, referring to FIG. 1I, a pixel electrode 180 which is electrically connected to the drain 154 through the opening 162 is fabricated through a seventh mask process. The fabrication of a pixel structure 100 of a conventional transflective LCD is hereby finished.
As shown in FIG. 1G, when forming the protection layer 160 as the plurality of bumps 166, an organic material has to be used to form the protection layer 160 such that the bumps 166 of high unevenness may be easily fabricated. Thus, with the exception of the material of the protection layer 160 being organic, the rest of the layers are inorganic materials. However, the characteristics of inorganic and organic materials are different, resulting in the requirement of using different fabrication parameters and a more complex fabrication process.
In addition, the abovementioned pixel structure 100 requires seven mask processes to fabricate the thin film transistor (comprising the gate 120, the source 152, as well as the drain 154) and the reflective layer 170. Hence, it is not easy to reduce the costs of the mask processes. Furthermore, it would also be difficult to raise productivity due to the higher number of fabrication processes.